With the development of technologies, electronic devices have more and more functions in life of people. For some electronic devices such as laptop computer, etc., a use may use a keyboard to input information. Alternatively, an ultrasonic electronic stylus may be utilized for inputting information into the electronic device.
Conventionally, in the case that the ultrasonic electronic stylus is utilized for inputting information into the electronic device, a pressure sensor is provided at the nib of the ultrasonic electronic stylus. When a user writes, if it is detected by the pressure sensor that a pressure generated on a writing board of the electronic device by the ultrasonic electronic stylus reaches a predetermined value, the ultrasonic electronic stylus starts to generate a signal. The electronic device may acquire locations of the ultrasonic electronic stylus with a signal receiver, thereby acquiring a corresponding stroke generated by the ultrasonic electronic stylus.
However, the inventor finds during research that, when a conventional method is used for stroke acquisition, since the user generally writes with a small force at the end of the stroke, the pressure sensed by the pressure sensor does not reach the predetermined value. Therefore, data for the end of the stroke is lost, and accordingly, the accuracy of stroke acquisition is low.